Reaction products of diazotised sodium 2-amino-5-{[2-(sulfonatooxy)ethyl]sulfonyl}benzenesulfonate coupled with sodium 2-(4-aminobenzene-1-sulfonyl)ethyl sulfate, subsequently coupled with diazotised sodium 2-(4-aminobenzene-1-sulfonyl)ethyl sulfate

Endpoint summary

Description of key information

Hydrolysis: On the basis of the experimental studies of the structurally similar read across chemical and applying the weight of evidence approach and by evaluating the hydrolysis of test chemical in water, the half-life, DT50 value of test chemical was found to be > 1 to < 46 years at pH 4 to 9 and temperature of 25°C.

 

Biodegradation in water:

The test chemical undergoes 59.38% biodegradation after 28 days in the test condition. Thus, the test chemical was considered to be inherently biodegradable in water.

 

Biodegradation in water and sediment

Estimation Programs Interface prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 2.85% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 180 days (4320 hrs). The half-life (180 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high whereas the half-life period of test chemical in sediment is estimated to be 1620.833 days (38900 hrs). Based on this half-life value, it indicates that test chemical is persistent in sediment.

Biodegradation in soil

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database. If released into the environment, 82.4% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 360 days (8640 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to high.

 

Adsorption: In accordance with column 2 of Annex VIII of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted because the substance has a low octanol-water partition coefficient and the adsorption potential of the substance is related to this parameter.

Additional information

Hydrolysis: 

Data available of the structurally similar read across chemicals has been reviewed to determine the hydrolysis of test chemical in water. The studies are as mentioned below:

 

The first study of hydrolysis was carried out for test chemical in water. The half-life, DT50 value of test chemical was found to be 46 years at pH 7 and temperature of 25°C. On the basis of result the test chemical was found to be stable in water. 

 

The second study of hydrolysis was carried out for test chemical in water. The half-life, DT50 value of test chemical was found to be > 1 year at pH 4 to 9. On the basis of result the test chemical was found to be stable in water. 

 

The third study of hydrolysis was carried out by Directive 84/449/EEC, C.10. The test was performed at pH 4, 7, and 9 and a temperature of 50 °C. Analytical monitoring of test substance was done by HPLC using an external standard. The buffered aqueous solutions were heated at 121 °C for 15 min before use to assure sterility. The exclusion of photolytic effects was done by using brown glass reaction flasks. The half-life, DT50 value of test chemical was found to be > 1 year at pH 4, 7 and 9 and a temperature of 25 °C. On the basis of result, the test chemical was found to be stable in water. 

 

On the basis of the experimental studies of the structurally similar read across chemical and applying the weight of evidence approach and by evaluating the hydrolysis of test chemical in water, the half-life, DT50 value of test chemical was found to be > 1 to < 46 years at pH 4 to 9 and temperature of 25°C. On the basis of result the test chemical was found to be stable in water

 

Biodegradation in water

Different experimental studies for the Biodegradation in water endpoint were reviewed for the test substance  and are summarised below:

 

The first study includes closed bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C. The test system included control, test chemical and reference chemical. Polyseed were used as inoculum at concentration of 10E7 to 10E8 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The initial concentration of test chemical and reference chemical (Sodium Benzoate) used was 4 mg/L, and the concentration of inoculum used was 32 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference chemical was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference chemical. The % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was observed to be 93.75%. Degradation of Sodium Benzoate exceeds 40.63% on 7 days & 90.63% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.48 mgO2/mg. ThOD was determined by calculation as 0.8 mgO2/mg. On the basis of ThOD and BOD 28 value the percent degradation of the test chemical was determined to be 59.38%. Based on the percent degradation value it is concluded that the test chemical was considered as inherently biodegradable in water.

 

The second study of biodegradation in water was carried out. The duration of test was 28 days. The inoculum was taken as activated sludge. The concentration of sludge was taken as 30 mg/L. The initial concentration of test chemical was taken as 100 mg/l. The study design was taken as standard type. The percent biodegradation of test chemical was determined to be 4% by O2 consumption parameter, 7 % by TOC parameter and 96 % by HPLC method. Based on the percent degradation value it is concluded that the test chemical is not readily biodegradable in water.

 

On the basis of the above-mentioned information, the test chemical was considered as not readily biodegradable in water.

 

Biodegradation in water and sediment

Estimation Programs Interface prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 2.85% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 180 days (4320 hrs). The half-life (180 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high whereas the half-life period of test chemical in sediment is estimated to be 1620.833 days (38900 hrs). Based on this half-life value, it indicates that test chemical is persistent in sediment.

 

Biodegradation in soil

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database. If released into the environment, 82.4% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 360 days (8640 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to high.

 

Adsorption: In accordance with column 2 of Annex VIII of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted because the substance has a low octanol water partition coefficient and the adsorption potential of the substance is related to this parameter.